Image sensor and an endoscope using the same

ABSTRACT

An endoscope having restricted dimensions and comprising at least one image gatherer, at least one image distorter and at least one image sensor shaped to fit within said limited dimensions, and wherein said image distorter is operable to distort an image received from said image gatherer so that the image is sensible at said shaped image sensor.

FIELD OF THE INVENTION

[0001] The present invention relates to an image sensor, and moreparticularly but not exclusively to two and three-dimensional opticalprocessing from within restricted spaces, and an endoscope using thesame.

BACKGROUND OF THE INVENTION

[0002] Endoscopy is a surgical technique that involves the use of anendoscope, to see images of the body's internal structures through verysmall incisions.

[0003] Endoscopic surgery has been used for decades in a number ofdifferent procedures, including gall bladder removal, tubal ligation,and knee surgery, and recently in plastic surgery including bothcosmetic and re-constructive procedures.

[0004] An endoscope may be a rigid or flexible endoscope which consistsof five basic parts: a tubular probe, a small camera head, a cameracontrol unit, a bright light source and a cable set which may include afiber optic cable. The endoscope is inserted through a small incision;and connected to a viewing screen which magnifies the transmitted imagesof the body's internal structures.

[0005] During surgery, the surgeon is able to view the surgical area bywatching the screen while moving the tube of the endoscope through thesurgical area.

[0006] In a typical surgical procedure using an endoscope, only a fewsmall incisions, each less than one inch long, are needed to insert theendoscope probe and other instruments. For some procedures, such asbreast augmentation, only two incisions may be necessary. For others,such as a forehead lift, three or four short incisions may be needed.The tiny eye of the endoscope camera allows a surgeon to view thesurgical site.

[0007] An advantage of the shorter incisions possible when using anendoscope is reduced damage to the patient's body from the surgery. Inparticular, the risk of sensory loss from nerve damage is decreased.However, most current endoscopes provide only flat, two-dimensionalimages which are not always sufficient for the requirements of thesurgery. The ability of an endoscope to provide three-dimensionalinformation in its output would extend the field of endoscope use withinsurgery.

[0008] The need for a 3D imaging ability within an endoscope has beenaddressed in the past. A number of solutions that provide stereoscopicimages by using two different optical paths are disclosed in PatentsU.S. Pat. No. 5,944,655, U.S. Pat. No. 5,222,477, U.S. Pat. No.4,651,201, U.S. Pat. No. 5,191,203, U.S. Pat. No. 5,122,650, U.S. Pat.No. 5,471,237, JP7163517A, U.S. Pat. No. 5,673,147, U.S. Pat. No.6,139,490, U.S. Pat. No. 5,603,687, WO9960916A2, and JP63244011A.

[0009] Another method, represented by U.S. Patents, U.S. Pat. No.5,728,044 and U.S. Pat. No. 5,575,754 makes use of an additional sensorthat provides location measurements of image points. Patent JP8220448Adiscloses a stereoscopic adapter for a one-eye endoscope, which uses anoptical assembly to divide and deflect the image to two sensors. Afurther method, disclosed in U.S. Pat. No. 6,009,189 uses imageacquisition from different directions using one or more cameras. Anattempt to obtain 3D information using two light sources was disclosedin U.S. Pat. No. 4,714,319 in which two light sources are used to givean illusion of a stereoscopic image based upon shadows. JP131622Adiscloses a method for achieving the illusion of a stereoscopic image byusing two light sources, which are turned on alternately.

[0010] An additional problem with current endoscopes is the issue oflighting of the subject for imaging. The interior spaces of the bodyhave to be illuminated in order to be imaged and thus the endoscopegenerally includes an illumination source. Different parts of the fieldto be illuminated are at different distances from the illuminationsource and relative reflection ratios depend strongly on relativedistances to the illumination source. The relative distances however maybe very large In a typical surgical field of view, distances can easilyrange between 2 and 20 cm giving a distance ratio of 1:10. Thecorresponding brightness ratio may then be 1:100, causing blinding andmaking the more distant object all but invisible.

[0011] One reference, JP61018915A, suggests solving the problem ofuneven lighting by using a liquid-crystal shutter element to reduce thetransmitted light. Other citations that discuss general regulation ofillumination levels include U.S. Pat. No. 4,967,269, JP4236934A,JP8114755A and JP8024219A.

[0012] In general it is desirable to reduce endoscope size and at thesame time to improve image quality. Furthermore, it is desirable toproduce a disposable endoscope, thus avoiding any need forsterilization, it being appreciated that sterilization of a complexelectronic item such as an endoscope being awkward in itself.

[0013] Efforts to design new head architecture have mainly concentratedon integration of the sensor, typically a CCD based sensor, with opticsat the distal end. Examples of such integration are disclosed in U.S.Pat. No. 4,604,992, U.S. Pat. No. 4,491,865, U.S. Pat. No. 4,692,608,JP60258515A, U.S. Pat. No. 4,746,203, U.S. Pat. No. 4,720,178, U.S. Pat.No. 5,166,787, U.S. Pat. No. 4,803,562, U.S. Pat. No. 5,594,497 andEP434793B1. Reducing the overall dimensions of the distal end of theendoscope are addressed in U.S. Pat. No. 5,376,960 and No. 4,819,065.and Japanese Patent Applications No. 7318815A and No. 70221A.Integration of the endoscope with other forms of imaging such asultrasound and Optical Coherence Tomography are disclosed in U.S. Pat.No. 4,869,256, U.S. Pat. No. 6,129,672, U.S. Pat. No. 6,099,475, U.S.Pat. No. 6,039,693, U.S. Pat. No. 55,022,399, U.S. Pat. No. 6,134,003and U.S. Pat. No. 6,010,449

[0014] Intra-vascular applications are disclosed in certain of theabove-mentioned patents, which integrate the endoscope with anultrasound sensor or other data acquisition devices. Patents thatdisclose methods for enabling visibility within opaque fluids are U.S.Pat. No. 4,576,146, U.S. Pat. No. 4,827,907, U.S. Pat. No. 5,010,875,U.S. Pat. No. 4,934,339, U.S. Pat. No. 6,178,346 and U.S. Pat. No.4,998,972.

[0015] Sterilization issues of different devices including endoscopesare discussed in WO9732534A1, U.S. Pat. No. 5,792,045 and U.S. Pat. No.5,498,230. In particular JP3264043A discloses a sleeve that wasdeveloped in order to overcome the need to sterilize the endoscope.

[0016] The above-mentioned solutions are however incomplete and aredifficult to integrate into a single endoscope optimized for all theabove issues.

SUMMARY OF THE INVENTION

[0017] It is an aim of the present embodiments to provide solutions tothe above issues that can be integrated into a single endoscope.

[0018] It is an aim of the embodiments to provide an endoscope that issmaller than current endoscopes but without any corresponding reductionin optical processing ability.

[0019] It is a further aim of the present embodiments to provide a 3Dimaging facility that can be incorporated into a reduced size endoscope.

[0020] It is a further aim of the present embodiments to provide objectillumination that is not subject to high contrast problems, for exampleby individual controlling of the light sources.

[0021] It is a further aim of the present embodiments to provide amodified endoscope that is simple and cost effective to manufacture andmay therefore be treated as a disposable item.

[0022] Embodiments of the present invention provide 3D imaging of anobject based upon photometry measurements of reflected light intensity.Such a method is relatively efficient and accurate and can beimplemented within the restricted dimensions of an endoscope.

[0023] According to a first aspect of the present invention there isthus provided a pixilated image sensor for insertion within a restrictedspace, the sensor comprising a plurality of pixels arranged in aselected image distortion pattern, said image distortion pattern beingselected to project an image larger than said restricted space to withinsaid restricted space substantially with retention of an imageresolution level.

[0024] Preferably, the image distortion pattern is a splitting of saidimage into two parts and wherein said pixilated image sensor comprisessaid pixels arranged in two discontinuous parts.

[0025] Preferably, the discontinuous parts are arranged in successivelengths.

[0026] Preferably, the restricted space is an interior longitudinal wallof an endoscope and wherein said discontinuous parts are arranged onsuccessive lengths of said interior longitudinal wall.

[0027] Preferably, the restricted space is an interior longitudinal wallof an endoscope and wherein said discontinuous parts are arranged onsuccessive lengths of said interior longitudinal wall.

[0028] Preferably, the distortion pattern is an astigmatic imagedistortion.

[0029] Preferably, the distortion pattern is a projection of an imageinto a rectangular shape having dimensions predetermined to fit withinsaid restricted space.

[0030] A preferred embodiment includes one of a group comprisingCMOS-based pixel sensors and CCD based pixel sensors.

[0031] A preferred embodiment is controllable to co-operate withalternating image illumination sources to produce uniform illuminatedimages for each illumination source.

[0032] According to a second aspect of the present invention there isprovided an endoscope having restricted dimensions and comprising atleast one image gatherer at least one image distorter and at least oneimage sensor shaped to fit within said restricted dimensions, andwherein said image distorter is operable to distort an image receivedfrom said image gatherer so that the image is sensible at said shapedimage sensor substantially with an original image resolution level.

[0033] Preferably, the image distorter comprises an image splitteroperable to split said image into two part images.

[0034] Preferably, the image sensor comprises two sensor parts, eachseparately arranged along longitudinal walls of said endoscope.

[0035] Preferably, the two parts are arranged in successive lengthsalong opposite longitudinal walls of said endoscope.

[0036] Preferably, the distorter is an astigmatic image distorter.

[0037] Preferably, the astigmatic image distorter is an imagerectangulator and said image sensor comprises sensing pixels rearrangedto complement rectangulation of said image by said image rectangulator.

[0038] Preferably, the image distorter comprises at least one lens.

[0039] Preferably, the image distorter comprises at least oneimage-distorting mirror.

[0040] Preferably, the image distorter comprises optical fibers to guideimage light substantially from said lens to said image sensor.

[0041] Preferably, the image distorter comprises a second lens.

[0042] Preferably, the image distorter comprises at least a secondimage-distorting mirror.

[0043] Preferably, the image distorter comprises at least one flatoptical plate.

[0044] A preferred embodiment comprises at least one light source forilluminating an object, said light source being controllable to flash atpredetermined times.

[0045] A preferred embodiment comprises a second light source, saidfirst and said second light sources each separately controllable toflash.

[0046] Preferably, the first light source is a white light source andsaid second light source is an IR source.

[0047] In a preferred embodiment, one light source being a right sidelight source for illuminating an object from a first side and the otherlight source being a left side light source for illuminating said objectfrom a second side.

[0048] In a preferred embodiment, one light source comprising light of afirst spectral response and the other light source comprising light of asecond spectral response.

[0049] A preferred embodiment further comprises color filters associatedwith said light gatherer to separate light from said image into rightand left images to be fed to respective right and left distancemeasurers to obtain right and left distance measurements forconstruction of a three-dimensional image.

[0050] In a preferred embodiment, said light sources are configured toflash alternately or simultaneously.

[0051] A preferred embodiment further comprises a relative brightnessmeasurer for obtaining relative brightnesses of points of said objectusing respective right and left illumination sources, thereby to deduce3 dimensional distance information of said object for use inconstruction of a 3 dimensional image thereof.

[0052] A preferred embodiment further comprises a second image gathererand a second image sensor.

[0053] Preferably, the first and said second image sensors are arrangedback to back longitudinally within said endoscope.

[0054] Preferably, the first and said second image sensors are arrangedsuccessively longitudinally along said endoscope.

[0055] Preferably, the first and said second image sensors are arrangedalong a longitudinal wall of s*d endoscope.

[0056] A preferred embodiment comprises a brightness averager operableto identify brightness differentials due to variations in distances fromsaid endoscope of objects being illuminated, and substantially to cancelsaid brightness differentials.

[0057] A preferred embodiment further comprises at least oneillumination source for illuminating an object with controllable widthlight pulses and wherein said brightness averager is operable to cancelsaid brightness differentials by controlling said widths.

[0058] A preferred embodiment has at least two controllable illuminationsources, one illumination source for emitting visible light to produce avisible spectrum image and one illumination source for emittinginvisible (i.e. IR or UV) light to produce a corresponding spectralresponse image, said endoscope being controllable to produce desiredratios of visible and invisible images.

[0059] According to a third aspect of the present invention there isprovided an endoscope system comprising an endoscope and a controller,said endoscope comprising:

[0060] at least one image gatherer,

[0061] at least one image distorter and

[0062] at least one image sensor shaped to fit within restricteddimensions of said endoscope, said image distorter being operable todistort an image received from said image gatherer so that the image issensible at said shaped image sensor with retention of image resolution,

[0063] said controller comprising a dedicated image processor forprocessing image output of said endoscope.

[0064] Preferably, the dedicated image processor is a motion videoprocessor operable to produce motion video from said image output.

[0065] Preferably, the dedicated image processor comprises a 3D modelerfor generating a 3D model from said image output.

[0066] Preferably, the said dedicated image processor further comprisesa 3D imager operable to generate a stereoscopic display from said 3Dmodel.

[0067] A preferred embodiment comprises an image recorder for recordingimaging.

[0068] A preferred embodiment comprises a control and displaycommunication link for remote control and remote viewing of said system.

[0069] Preferably, the image distorter comprises an image splitteroperable to split said image into two part images.

[0070] Preferably, the image sensor comprises two sensor parts, eachseparately arranged along longitudinal walls of said endoscope.

[0071] Preferably, the two parts are arranged in successive lengthsalong opposite longitudinal walls of said endoscope.

[0072] Preferably, the distorter is an astigmatic image distorter.

[0073] Preferably, the astigmatic image distorter is an imagerectangulator and said image sensor comprises sensing pixels rearrangedto complement rectangulation of said image by said image rectangulator.

[0074] Preferably, the image distorter comprises at least one lens.

[0075] Preferably, the image distorter comprises at least oneimage-distorting mirror.

[0076] Preferably, the image distorter comprises optical fibers to guideimage light substantially from said lens to said image sensor.

[0077] Preferably, the image distorter comprises a second lens.

[0078] Preferably, the image distorter comprises at least a secondimage-distorting mirror.

[0079] Preferably, the image distorter comprises at least one flatoptical plate.

[0080] A preferred embodiment further comprises at least one lightsource for illuminating an object.

[0081] A preferred embodiment comprises a second light source, saidfirst and said second light sources each separately controllable toflash.

[0082] Preferably, the first light source is a white light source andsaid second light source is an invisible source.

[0083] In a preferred embodiment, one light source is a right side lightsource for illuminating an object from a first side and the other lightsource is a left side light source for illuminating said object from asecond side.

[0084] In a preferred embodiment, one light source comprises light of afirst spectral response and the other light source comprises light of asecond spectral response.

[0085] A preferred embodiment comprises color filters associated withsaid light gatherer to separate light from said image into right andleft images to be fed to respective right and left distance measurers toobtain right and left distance measurements for construction of athree-dimensional image.

[0086] Preferably, the light sources are configured to flash alternatelyor simultaneously.

[0087] A preferred embodiment further comprises a relative brightnessmeasurer for obtaining relative brightnesses of points of said objectusing respective right and left illumination sources, thereby to deduce3 dimensional distance information of said object for use inconstruction of a 3 dimensional image thereof.

[0088] A preferred embodiment further comprises a second image gathererand a second image sensor.

[0089] Preferably, the first and said second image sensors are arrangedback to back longitudinally within said endoscope.

[0090] Preferably, the first and said second image sensors are arrangedsuccessively longitudinally along said endoscope.

[0091] Preferably, the first and said second image sensors are arrangedalong a longitudinal wall of said endoscope.

[0092] A preferred embodiment comprises a brightness averager operableto identify brightness differentials due to variations in distances fromsaid endoscope of objects being illuminated, and substantially to reducesaid brightness differentials.

[0093] According to a fifth embodiment of the present invention there isprovided an endoscope for internally producing an image of a field ofview, said image occupying an area larger than a cross-sectional area ofsaid endoscope, the endoscope comprising:

[0094] an image distorter for distorting light received from said fieldof view into a compact shape, and

[0095] an image sensor arranged in said compact shape to receive saiddistorted light to form an image thereon.

[0096] A preferred embodiment comprises longitudinal walls, wherein saidimage sensor is arranged along said longitudinal walls, the endoscopefurther comprising a light diverter for diverting said light towardssaid image sensor.

[0097] Preferably, the image sensor comprises two parts, said distortercomprises an image splitter for splitting said image into two parts, andsaid light diverter is arranged to send light of each image part to arespective part of said image sensor.

[0098] Preferably, the sensor parts are aligned on facing lengths ofinternal sides of said longitudinal walls of said endoscope.

[0099] Preferably, the sensor parts are aligned successivelylongitudinally along an internal side of one of said walls of saidendoscope.

[0100] A preferred embodiment of the image distorter comprises anastigmatic lens shaped to distort a square image into a rectangularshape of substantially equivalent area.

[0101] A preferred embodiment further comprises a contrast equalizer forcompensating for high contrasts differences due to differentialdistances of objects in said field of view.

[0102] A preferred embodiment comprises two illumination sources forilluminating said field of view.

[0103] In a preferred embodiment, the illumination sources arecontrollable to illuminate alternately, and said image sensor iscontrollable to gather images in synchronization with said illuminationsources thereby to obtain independently illuminated images.

[0104] In a preferred embodiment, each illumination source is of adifferent predetermined spectral response.

[0105] A preferred embodiment of said image sensor comprises pixels,each pixel being responsive to one of said predetermined spectralresponses.

[0106] A preferred embodiment of the image sensor comprises a pluralityof pixels responsive to white light.

[0107] In a preferred embodiment, said image sensor comprises aplurality of pixels responsive to different wavelengths of light.

[0108] In a preferred embodiment, the wavelengths used comprise at leastthree of red light, green light, blue light and infra-red light.

[0109] In a preferred embodiment, a second image sensor forms a secondimage from light obtained from said field of view.

[0110] In a preferred embodiment, said second image sensor is placed inback to back relationship with said first image sensor over alongitudinal axis of said endoscope.

[0111] In a preferred embodiment, the second image sensor is placed inend to end relationship with said first image sensor along alongitudinal wall of said endoscope.

[0112] In a preferred embodiment, the second image sensor is placedacross from said first image sensor on facing internal longitudinalwalls of said endoscope.

[0113] According to a sixth embodiment of the present invention there isprovided a compact endoscope for producing 3D images of a field of view,comprising a first image sensor for receiving a view of said fieldthrough a first optical path and a second image sensor for receiving aview of said field through a second optical path, and wherein said firstand said second image sensors are placed back to back along alongitudinal axis of said endoscope.

[0114] According to a seventh embodiment of the present invention thereis provided a compact endoscope for producing 3D images of a field ofview, comprising a first image sensor for receiving a view of said fieldthrough a first optical path and a second image sensor for receiving aview of said field through a second optical path, and wherein said firstand said second image sensors are placed end to end along a longitudinalwall of said endoscope.

[0115] According to an eighth embodiment of the present invention thereis provided a compact endoscope for producing 3D images of a field ofview, comprising two illumination sources for illuminating said field ofview, an image sensor for receiving a view of said field illuminated viaeach of said illumination sources, and a view differentiator fordifferentiating between each view.

[0116] Preferably, the differentiator is a sequential control forproviding sequential operation of said illumination sources.

[0117] Preferably, the illumination sources are each operable to produceillumination at respectively different spectral responses and saiddifferentiator comprises a series of filters at said image sensor fordifferentially sensing light at said respectively different spectralresponses.

[0118] Preferably, the image distorter comprises a plurality of opticalfibers for guiding parts of a received image to said image sensoraccording to said distortion pattern.

[0119] According to a ninth embodiment of the present invention there isprovided a method of manufacturing a compact endoscope, comprising:

[0120] providing an illumination source,

[0121] providing an image distorter,

[0122] providing an image ray diverter,

[0123] providing an image sensor whose shape has been altered tocorrespond to a distortion built into said image distorter, saiddistortion being selected to reduce at least one dimension of said imagesensor to less than that of an undistorted version being sensed,

[0124] assembling said image distorter, said image ray diverter and saidimage sensor to form an optical path within an endoscope

[0125] According to a tenth embodiment of the present invention there isprovided a method of obtaining an endoscopic image comprising:

[0126] illuminating a field of view,

[0127] distorting light reflected from said field of view such as toform a distorted image of said field of view having at least onedimension reduced in comparison to an equivalent dimension of saidundistorted image, and

[0128] sensing said light within said endoscope using at least one imagesensor correspondingly distorted.

BRIEF DESCRIPTION OF THE DRAWINGS

[0129] For a better understanding of the invention and to show how thesame may be carried into effect, reference will now be made, purely byway of example, to the accompanying drawings, in which:

[0130]FIG. 1 is a simplified block diagram of an endoscope system towhich embodiments of the present invention may be applied, FIG. 2 is asimplified block diagram of an endoscope system according to a firstembodiment of the present invention,

[0131]FIG. 3 is a simplified block diagram of a wireless modification ofthe endoscope of FIG. 2,

[0132]FIG. 4 is a simplified schematic block diagram of an endoscopeaccording to a preferred embodiment of the present invention,

[0133]FIG. 5 is a simplified ray diagram showing optical paths within anendoscope according to a preferred embodiment of the present invention,

[0134]FIG. 6 is a ray diagram view from a different angle of theembodiment of FIG. 5,

[0135]FIG. 7 is a ray diagram showing an alternative construction of anoptical assembly according to a preferred embodiment of the presentinvention,

[0136]FIG. 8 is a ray diagram showing a further alternative constructionof an optical assembly according to a preferred embodiment of thepresent invention,

[0137]FIG. 9 is a ray diagram showing yet a further alternativeconstruction of the optical assembly according to a preferred embodimentof the present invention,

[0138]FIG. 10 is a ray diagram taken from the front, of the embodimentof FIG. 9,

[0139]FIG. 11 is a ray diagram showing yet a further alternativeconstruction of an optical assembly according to a preferred embodimentof the present invention,

[0140]FIG. 12 is a simplified layout diagram of an image sensoraccording to an embodiment of the present invention,

[0141]FIG. 13 is a simplified ray diagram showing an endoscope for usein a stereoscopic mode according to a preferred embodiment of thepresent invention,

[0142]FIG. 14 is a simplified ray diagram showing how a 3D modelobtained from the embodiment of FIG. 13 can be used to construct astereoscopic image of the field of view,

[0143]FIG. 15A is a simplified diagram in cross-sectional view showingan arrangement of the image sensors in a stereoscopic endoscopeaccording to a preferred embodiment of the present invention,

[0144]FIG. 15B is a view from one end of the arrangement of FIG. 15A,

[0145]FIG. 16 is a simplified ray diagram showing an alternativearrangement of sensors for obtaining a stereoscopic image of a field ofview according to a preferred embodiment of the present invention,

[0146]FIG. 17 is a simplified block diagram of a network portableendoscope and associated hardware usable with preferred embodiments ofthe present invention,

[0147]FIG. 18 is a simplified block diagram of an endoscope adapted toperform minimal invasive surgery and usable with the preferredembodiments of the present invention,

[0148]FIG. 19 is a simplified block diagram of an enhanced endoscopesystem for use in research,

[0149]FIG. 20 is a simplified block diagram of a configuration of anendoscope system for obtaining stereoscopic images, and usable with thepreferred embodiments of the present invention, and

[0150]FIG. 21 is a simplified block diagram of a system for use inintravascular procedures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0151] The present embodiments provide a diagnostic and operative systemfor minimally invasive diagnosis and surgery procedures, and othermedical and non-medical viewing applications, in particular in whichaccess conditions dictate the use of small-dimension viewing devices.

[0152] Reference is now made to FIG. 1, which is a basic block diagramof a basic configuration of an endoscope according to a first embodimentof the present invention. The figure snows a basic configuration of theendoscopic system including interconnections. The configurationcomprises a miniature endoscopic front-end 10, hereinafter simplyreferred to as an endoscope, attached by a wire connection 20 to aprocessing device 30, typically a PC, the PC having appropriate softwarefor carrying out image processing of the output of the endoscope. Theskilled person will appreciate that the wire connection 20 may be anoptical connection or may instead use RF or a like means of wirelesscommunication. The miniature endoscopic front-end 10 may be designed forconnection to any standard PC input (the USB input for example).

[0153] The software included with processing device 30 processes theoutput of the miniature endoscopic front-end 10. The software maytypically control transfer of the images to the monitor of the PC 30 andtheir display thereon including steps of 3D modeling based onstereoscopic information as will be described below, and may controlinternal features of the endoscopic front end 10 including lightintensity, and automatic gain control (AGC), again as will be describedbelow.

[0154] Reference is now made to FIG. 2, which is an internal blockdiagram of an endoscope according to a preferred embodiment of thepresent invention. A miniature endoscope 40 is connected by a wire 42 toan adapter 44. The endoscope 40 comprises an image sensor 46 which maytypically comprise a CMOS or CCD or like sensing technology, an opticalassembly 48, a light or illumination source 50, communication interface52 and controller 54. The wired unit of FIG. 2 preferably includes avoltage regulator 56.

[0155] As will be explained in more detail below, the image sensor 46 isaligned along the length of a longitudinal side-wall (that is to saysubstantially in parallel with the wall and at least not perpendicularthereto) of the endoscope 40. Such an alignment enables the radialdimension of the endoscope to be reduced beyond the diagonal of theimage sensor 46. Preferably the sensor is arranged in two parts, as willbe explained below.

[0156] Reference is now made to FIG. 3, which is an internal blockdiagram of a wireless equivalent of the embodiment of FIG. 2. Parts thatare identical to those shown above are given the same reference numeralsand are not referred to again except as necessary for an understandingof the present embodiment. In the embodiment of FIG. 3, the wire 42 isreplaced by a wireless link 56 such as an IR or RF link with appropriatesensor, and a battery pack 58.

[0157] Reference is now made to FIG. 4, which is an schematic blockdiagram of the miniature endoscope according to a preferred embodimentof the present invention. Parts that are identical to those shown aboveare given the same reference numerals and are not referred to againexcept as necessary for an understanding of the present embodiment.Optical assembly 48 receives light, indicated by arrows 60, from anobject being viewed. The light is processed by optical assembly 48, aswill be explained below, to reach image sensor 46 were it is convertedfrom photons into electrical signals. The electrical signals aredigitized and passed to a transmitting device 62, for example an LVDStransmitter, which drives the data through communication link 20 andadapter 44 to the processing device 30.

[0158] Operating power for the endoscope 40 is preferably provided,through adapter 44, to the voltage regulator 56. Control of thefront-end is preferably carried out by the processor device 30 asdiscussed above. Control data from the processing device 30 ispreferably received at the endoscope 40 by a receiving device 64, whichmay typically be an LVDS receiver. Hard wired logic 66 preferably servesas an interface to convert the incoming control data into signals forcontrolling both the sensor 46 and the light source 50.

[0159] The light source 50 preferably comprises one or more lighttransmitting devices such as LEDs, typically a left light source 68 andright light source 70. The left and right light sources may becontrollable through a driver 72. The functions of each of the abovecomponents are described in greater detail below. As the skilled personwill be aware, use of CMOS and similar technologies for the sensorspermit the sensor 46, the transmitting device 62, the receiving device64, the hard wired logic 66, the driver 72 and the voltage regulator 56to be integrated into a single semiconductor Integrated Circuit and suchintegration is particularly advantageous in achieving a compact designof endoscope.

[0160] Considering the light source 50 in greater detail, it preferablycomprises an integrated array of several white light sources (LEDs forexample) with energy emission in the visible light range mixed,optionally, with IR light sources (LEDs) for purposes that will beexplained below. In fact, any combination of spectral responses may beused, particularly preferred combinations including red+IR andgreen+blue. An integrated array of light sources allows control of eachlight source individually facilitating the following features:

[0161] The System is able to turn on the white light source and the IRLight source in sequence to generate an IR image every N (userdetermined) standard white images, for detection by a sensorconfiguration to be described below with respect to FIG. 12.

[0162] The objects being imaged are generally located at a range ofdifferent distances or field depths from the light source and areconsequently unevenly illuminated. The more distant areas in the fieldare dark and are almost invisible while the nearer areas are bright andcan become saturated. In order to compensate for the uneven illuminationintensity over the field, the system preferably exerts control over theintensity of each light source individually, thereby to compensate forreflected intensity of the objects. An example of an algorithm forcontrol of the illumination array is given as follows:

[0163] Given N individual light sources in the illumination array in thecamera head, an initialization process is carried out to generate areference image, preferably a homogeneous white object, to be stored foreach light source. The stored reference images (matrices) are identifiedhereinbelow by RIi where i=1,2 . . . N

[0164] Following initialization, imaging is carried out and the inputimage of the field (indicated by matrix II) is divided into M areas suchthat: M>N. The image areas are identified hereinbelow by Sj j=1,2, . . .M

[0165] Following the above imaging stage, an inner product matrix iscalculated such that element Tij of the inner product matrix reflectsthe inner product resulting from taking the II matrix and performingmatrix multiplication with the RIi matrix, in the area Sj and summingthe elements of the result metrics.

[0166] The resulting inner product matrix is given by T where: M$T = {{\begin{matrix}{t11} & {t12} & \ldots & {t1M} \\{t21} & \ldots & \ldots & {t2M} \\{tN1} & \ldots & \ldots & {tNM}\end{matrix}}N\quad {and}}$${Tij} = {{1/{Sj}}\quad {\sum\limits_{P = 1}^{Sj}{{{Pij}\left( {{xp},{yp}} \right)} \cdot {{Rj}\left( {{xp},{yp}} \right)}}}}$

[0167] wherein

[0168] Pij—the intensity of the pixel located in (xp,yp) resulting fromlight source i in area j

[0169] Rj—the intensity of the pixel located in (xp,yp) resulting fromthe input image in area j

[0170] Sj—the total pixels in area j

[0171] xp,yp—the pixels coordinates in area j

[0172] Next, a vector v is determined that satisfies the following:

Tv−k→Min, where

[0173] v—the vector of intensities of each source, and

[0174] k—the vector of the desired common intensity, and the solution tothis requirement is given by

v =(T ^(T) ·T)⁻¹ ·T ^(T) ˜k

[0175] The central control unit preferably uses the above algorithm topost-process the data to reconstruct a natural look of the image,thereby to compensate for brightness non-uniformities.

[0176] In the case of using LEDs as the light source, their fastresponse time makes it possible to operate them in a“controllable-flash” mode, replacing the need for variable integrationtime (or AGC).

[0177] Referring now to the image sensor 46, as observed above inrespect of FIG. 2, in the prior art endoscope the size of the sensorprovides a limitation on the transverse diameter of the endoscope. Thus,in the present embodiment, in order to remove the limitation the sensoris placed along the longitudinal wall of the endoscope, again preferablysubstantially parallel to the wall but at least not perpendicularthereto. The use of the longitudinal wall not only gives greater freedomto reduce the transverse diameter of the endoscope but also gives thefreedom to increase the length of the sensor, thus increasing imageresolution in the horizontal sense.

[0178] As will be explained below, there are two specific embodiments ofthe realigned sensor, each one associated with a respective design ofthe optical assembly as will be described in detail below.

[0179] In addition to the above-mentioned geometrical realignment, thesensor may be supplied with color filters to allow acquisition of IRimages for diagnostic purposes or 3D imaging, again as will be describedin detail below.

[0180] Referring now to the geometric design of the sensor, as will beappreciated, the sensor comprises a field of pixels arranged in an arrayover an image-gathering field. The first specific embodiment comprises arearrangement of the pixels in the sensor. Given that for the purposesof example, the sensor width may be divided into say two parts, then thetwo parts may be placed end to end lengthwise. Thus, for example, a512×512 pixels' sensor with pixel dimensions of 10×10 micron, may bedivided into two sections of width 256 pixels each to be placed end toend to give a sensor of 256×1024 pixels and having an overall imagingarea of 2.56 mm×10.24 mm. The longer dimension is preferably placedalong the lengthwise dimension of the endoscope, thus permitting reduceddiameter of the endoscope with no corresponding reduction in theprecision level of the image.

[0181] The second specific embodiment likewise relates to a geometricalrearrangement of the pixels. The prior art image sensor has a round orsquare overall sensor or pixilated area, however, if the same number ofpixels are arranged as a rectangle having the same area as the originalsensor but with the height and width freely chosen then the width may beselected to be smaller than the width of the equivalent prior artsensor. More particularly, for an exemplary 512×512 pixels' sensor withpixel dimensions of 10×10 micron the standard prior art sensor (whichwill have a width of 5.12 mm) may be replaced by a rectangular sensorhaving the same overall sensing area as in the previous specificembodiment, but with specific width height dimensions of 2.56 mm×10.24mm, thus becoming easier to fit in the endoscope.

[0182] Reference is now made to FIG. 5, which is a ray diagram showing asimplified view from above of optical paths within the endoscope. Aswill be appreciated, in order for the image sensors of the specificembodiments referred to above to produce images which can be recreatedin an undistorted fashion, each sensor is preferably associated with anoptical assembly which is able to redirect image parts in accordancewith the rearrangements of the pixels.

[0183]FIG. 5 shows a version of optical assembly 48 designed for thefirst of the two specific embodiments of the image sensor, namely thatinvolving the widthwise transfer of pixels. A side view of the sameoptical assembly is shown in FIG. 6. FIG. 5 shows a point source object80, from which light reaches two lenses 82 and 84. The two lenses areselected and arranged to divide the light into two parts, which partsreach a front-surface-mirror 86. The front surface mirror sends eachpart of the image to a different part of the sensor 46, and recovery ofthe image is possible by appropriate wiring or addressing of the sensorpixels to recover the original image shape.

[0184] Reference is now made to FIG. 7 which is a ray diagram showing analternative version of optical assembly 48, again designed for the firstspecific embodiment of the image sensor. A single lens 86 is positionedin conjunction with two front-surface-mirrors 88 and 90 to deflect lightfrom the object 80 to the mirrors. Each of the two front surface mirrorsrespectively transfers half of the image to the upper or lower part ofthe sensor 46.

[0185] Reference is now made to FIG. 8, which is a ray diagram showing athird embodiment of the optical assembly 48, this time for the second ofthe specific embodiments of the image sensor 46, namely the embodimentin which the square shape of pixels is reduced to a rectangular shapehaving smaller width. An asymmetric or astigmatic lens 92 is arranged tofocus light onto a front-surface-mirror 94. The light is distorted bythe lens 92 to undo the distortion introduced into the image by therectangular shape of the sensor 46, and then it is reflected by themirror 94 onto the surface of the sensor 46.

[0186] Reference is now made to FIG. 9, which is a ray diagram takenfrom the side showing a further embodiment of the optical assembly 48.The embodiment of FIG. 8 necessitates a relatively complicated design ofthe mirror, and in order to obviate such complexity, additional opticaldes is shown. As shown in FIG. 9, the same astigmatic lens 92 is placed,not in front of a mirror but rather in front of a series of flat opticalplates 96 .l..96 .n, each comprising a diagonal lateral cross section,the plates each reflecting the light through the respective plate to thesurface of sensor 46.

[0187] Reference is additionally made to FIG. 10, which is a raydiagram, taken from the front, of the series of optical plates 96 ofFIG. 9. A comparison between the perspectives of FIG. 9 and FIG. 10 showthe layout of the plates with respect to the endoscope.

[0188] Reference is now made to FIG. 11, which is a simplified raydiagram showing a further embodiment of the optical assembly 48. In theembodiment of FIG. 11, a single lens 98 is preferably used to focuslight from an object 80 to a plane 100 shown in dotted lines. A seriesof optical fibers 102 are lined up over the surface of plane 100 toguide light to desired portions of the surface of the image sensor 46.The fibers 102 are able to direct light as desired and thus can be usedin combination with any arrangement of the sensor pixels that isdesired.

[0189] Returning to the construction of the image sensor 46, referenceis now made to FIG. 12, which is a layout diagram showing a layout ofpixels on a sensory surface of an embodiment of the image sensor 46. InFIG. 12, an array comprising pixels of four types is shown, red r, greeng, blue b and infra-red IR. The pixels are evenly spaced and allowacquisition of a colored image when used in conjunction with white lightor an IR image when used in conjunction with an IR source.

[0190] In many cases, important medical information is contained at IRwavelengths. In order to allow acquisition of IR images, the sensor ispreferably designed as described above, and using inter alia pixels IRfilters, that is to say color filters that have band passes at IRwavelengths. The sensor is placed in an endoscope in association witheither one or both of a source of visible light and a source ofinfra-red light. Use of the appropriate one of the two light sourcespermits acquisition of either color frames or IR frames as desired. Inone preferred embodiment, IR and color frames are obtainedsimultaneously by operating color and IR light sources together andallowing each pixel to pick up the waveband it has been designed for. Inanother preferred embodiment the color and IR light sources are operatedseparately. Typically one IR frame would be prepared and sent for everyseveral color frames.

[0191] Reference is now made to FIG. 13, which is a simplified raydiagram showing how the endoscope may be used in a stereoscopic mode.The stereoscopic mode permits the production of 3D images. As withprevious figures the ray diagram indicates rays emanating from a singlepoint, and the skilled person will appreciate how to extrapolate to afull image.

[0192] In FIG. 13, an endoscope comprises two separate white lightsources 110 and 112 located at opposite sides of a front opening of theendoscope, respectively being a left light source 110 and a right lightsource 112. The two white light sources are controlled to light in turnin successive short flashes to illuminate an object 114. Light reflectedby the object 114 returns to the endoscope where it strikes a lens 115placed across the front opening and where it is focused on to the planeof sensor 46. The sensor detects the illumination level, which differsbetween the left and right light beams. The ratio of the illuminationlevels may be used to calculate the position of the object and therebyto build up a 3D distance database, as will be explained in greaterdetail below.

[0193] As mentioned above, in the stereoscopic mode the left and rightlight sources are used sequentially. Comparison between left and rightilluminated images allows a 3D database to be constructed, enablingstereoscopic display of the scene. In the present embodiment, thecomparison between the images is based upon photometry measurements. InFIG. 13, an image 116 of object 114 may be considered as comprising aseries of activated x, y, locations on the detection plane of the sensor46. For each of the x, y locations forming the image 116 on the sensor46, a ratio between the Right Illuminated Image (RII) and the LeftIlluminated Image (LII) may be discerned. The detected ratio may differover the image as it is a function in each case of the distances of therespective light source to the object 114. The left light source 110 andthe right light source 112 have a distance between them which is twiced, d being the length of arrow 117, and the lens has a focal length of1/f, where f is the length of arrow 118. The distance from the lens 115to the plane of the object 114 is denoted by Z and is indicated by arrow120.

[0194] The Left Beam Length (LBL) can thus be expressed by:

LBL={square root}[Z ²+(X−d)²]+{square root}[(Z+1/f)²+(X+x) ²]

[0195] while the Right Beam Length (RBL) is given by:

RBL={square root}[Z ²+(X+d)²]+{square root}[(Z+1/f)²+(X+x)²]

[0196] where:

X=xZf

[0197] Thus the ratio of the light intensity between the left and rightlight sources, which is the inverted square of the distance LBL/RBL, maybe expressed as:

LeftToRightRatio=(LBL/RBL)⁽⁻²⁾

[0198] The image 116, obtained as described above may now be stored interms of a 3D model. The 3D model is preferably displayed as a 3D imageby constructing therefrom two stereoscopic images. The conversion may beperformed using conversion formulae as follows:

yl=yr=−Y/(Z*f)

xl=(−X−D/2)/(Z*t)

xr=(−X+D/2)/(Z*f)

[0199]FIG. 13 thus shows how an image of the object can be stored as a3D data base. 3D data of the object is obtained as described above andstored as a database.

[0200] Reference is now made to FIG. 14, which is a further simplifiedray diagram showing, by means of rays, how the 3D model or database ofFIG. 13 can be used to obtain a 3D effect at the eyes of an observer. Inorder to display the 3D information using a standard 2D display(monitor) the database is converted into two separate stereoscopicimages, and a display device is used to display each one of thestereoscopic images to a different eye. For example the device may be apair of glasses having a controllable shutter on each on of the eyes.

[0201] In FIG. 14, X, Y, 114 and Z 120 represents the three dimensionsto be used in the image 119, which corresponds to image 116 as stored inthe previous figure, the object being to reproduce the three dimensionalcharacter of the image by showing different projections of the image toeach of the two eyes of a viewer.

[0202] line 122 represents a projected location on the left image.

[0203] Line 124 represents the same projected location as it appears onthe right image.

[0204] 1/f 118 is the focal length (the amplification factor).

[0205] D 126 is the distance between the lenses 128 (representing theeyes).

[0206] A preferred embodiment for producing a 3D model using theendoscope uses different color left and right light sources in place ofwhite light sources. Thus, instead of sequentially illuminating theobject from either side, it is possible to illuminate the imagesimultaneously using both sources and to use appropriate filters toseparate the left and right brightness information. For example a leftillumination source 110 may be green and right illumination source 112may be a combination of red+blue. Such a two-color embodiment isadvantageous in that it is simple to control and avoids image distortionproblems due to the time lag between acquisitions of the two separateimages.

[0207] In one alternative embodiment, one of the light sources 110, 112is a visible light source and the second light source is an IR lightsource. In the case of an IR light source color filters at the sensorpreferably include an IR pass filter. The sensor of FIG. 12, with anarrangement of IR, red, green and blue detectors as described above maybe used.

[0208] Reference is now made to FIGS. 15A and 15B which are simplifiedschematic diagrams showing an endoscope according to a preferredembodiment of the present invention for obtaining dual sensorstereoscopic imaging, as will be explained below. FIG. 15A is a sidesectional view and FIG. 15B is a front view.

[0209] In the embodiment of FIG. 15A two image sensors 140 and 142 aresituated back to back along a plane of the central axis of an endoscope144. Each image sensor 140 and 142 is associated with a respectiveoptical assembly comprising a lens 150 and 152 and a mirror 154 and 156.The respective light source 146, 148, illuminates the entire field ofview as described above and light is gathered by the lens and directedby the mirror onto the sensor. The sensors are preferably mounted on asingle PCB 158.

[0210]FIG. 15B is a view from the front of the endoscope of FIG. 15A. Itwill be noticed that a third optical light source 158 shown. Since thestereoscopic aspect of the image is obtained from the use of two opticalimage paths, as opposed to the previous embodiments which used differentlight sources and different object optical paths, there is now freedomto use any number of light sources as desired to produce desired color(or IR) information.

[0211] The back-to-back arrangement of the sensors 140 and 142 along thecentral axis of the endoscope 144 ensures that the endoscope dimensionsare minimized both lengthwise and radially.

[0212] Reference is now made to FIG. 16, which is an alternativeembodiment of an endoscope for obtaining dual sensor stereoscopicimaging. An endoscope 160 comprises two image sensors 162 and 164arranged in a head to tail arrangement along one longitudinal wall ofthe endoscope, and again, as above, preferably parallel to the wall andat least not perpendicular thereto. Illumination sources 166 and 168 arelocated at a front end 170 of the endoscope and located at the peripherythereof. Two lenses 172 and 174 direct light received from a field ofview onto respective mirrors 176 and 178 each of which is arranged todeflect the light onto one of the sensors. Each image sensor 162 and 164thus provides a slightly different image of the field of view.

[0213] It is emphasized that the dual sensor configuration does notdecrease the overall image resolution, because, in accordance with theabove configurations, two full-size image sensors may be used.

[0214] The two versions of an endoscope for obtaining dual sensorstereoscopic imaging described above can make use of image sensorseither with or without color filters. However the sensor of FIG. 12could be used for one or both of the sensors in either of theembodiments above.

[0215] A further preferred embodiment uses a monochrome sensor for oneof the two image sensors and a color sensor for the second. Such acombination of one monochrome sensor and one color-filtered sensor inthe unit improves the resolution of the overall image and thesensitivity and dynamic range of the endoscope.

[0216] The above embodiments have been described in accordance with thegeneral endoscope layout given in FIG. 1. In the following, alternativeendoscopic system configurations are described.

[0217] Reference is now made to FIG. 17, which is a simplified blockdiagram of a network portable endoscope and associated hardware. Partsthat are identical to those shown above are given the same referencenumerals and are not referred to again except as necessary for anunderstanding of the present embodiment. An endoscope 10 is connected toa central control unit 180 where dedicated image processing takes place.The control unit 180 allows for full motion video to be produced fromthe signals emitted by the endoscope. The control unit is connected to alocal display device 182. Additionally or alternatively, a remotecontrol and viewing link 183 may be used to allow remote monitoring andcontrol of the endoscope. The endoscope 10 is preferably a portabledevice and may be powered from a battery pack 184.

[0218] Reference is now made to FIG. 18, which is a simplified blockdiagram of an endoscope adapted to perform minimal invasive surgery(MIS). Parts that are identical to those shown above are given the samereference numerals and are not referred to again except as necessary foran understanding of the present embodiment. The most common use ofendoscopic systems is for the performance of MIS procedures by thesurgeon in the operating room. The use of a reduced size endoscopeaccording to the above embodiments enables new procedures to beperformed in which minimal dimensions of the operating equipment isimportant. In FIG. 18, the endoscope 10 is connected to a rack 190. Therack contains accomodation for a full range of equipment that may berequired in the course of use of the endoscope in the operating room,for example a central control unit 180, a high quality monitor 182, aninsufflator 186 etc.

[0219] The configuration of FIG. 18, by virtue of the dedicated imageprocessing provided with the control unit 180, gives full motion videowithout requiring fiber-optic and camera head cables.

[0220] Reference is now made to FIG. 19, which is a simplified blockdiagram showing an enhanced version of the endoscope for use inresearch. Parts that are identical to those shown above are given thesame reference numerals and are not referred to again except asnecessary for an understanding of the present embodiment. The systemcomprises a miniature endoscopic front-end 10 connected to a highlyintegrated PC based central control unit 200 via communication link 20.

[0221] The central control unit uses dedicated image processing and thusenables full motion video, displayable locally on display device 182 orremotely via control and display link 183. An optional printer 202 isprovided to print documents and images, including images taken via theendoscope, of the pathologies or stages of the procedure. The systempreferably includes a VCR 204 for recording video produced by theendoscope and a digital storage device 206 allowing archiving of thewhole video. As mentioned above, the system can also be connected viaremote control and viewing link 183, to a remote site for teaching orfor using medical help and guidance. In some hospitals and operatingrooms, in addition to regular operating procedures, research is carriedout. Research procedures generally require additional documentation andcommunication functions. In order to support those requirements a PCbased system with high documentation and communication capabilities isprovided by the enhanced control unit 200. In addition to the externaldevices, an image enhancement software package is used, allowing thegeneration of high quality hard copies of images.

[0222] Reference is now made to FIG. 20, which is a simplified blockdiagram showing a configuration of endoscope for obtaining stereoscopic(3D) images. Parts that are identical to those shown above are given thesame reference numerals and are not referred to again except asnecessary for an understanding of the present embodiment. The miniatureendoscope 10 is connected via a communication link 20 as before to a 3Dcentral control unit 210, which is the same as the previous control unit200 except that it has the additional capability to construct a 3D modelfrom image information provided by the endoscope. The 3D model can thenbe projected to form a 3D image on a 3D stereoscopic display system 212.The configuration of FIG. 20 may be combined with features taken fromany of the embodiments referred to above.

[0223] Recently, new operating procedures requiring stereoscopic (3D)display have been developed. In particular such new applicationsinvolved minimally invasive heart and brain procedures. The 3D imagingembodiments referred to above, which may be grouped into multiple lightsource based imaging and dual optical path imaging, can give thenecessary information to construct a 3D model of the scene and togenerate stereoscopic images therefrom.

[0224] Reference is now made to FIG. 21, which is a simplified blockdiagram showing a variation of an endoscope system for use inintra-vascular procedures. Parts that are identical to those shown aboveare given the same reference numerals and are not referred to againexcept as necessary for an understanding of the present embodiment. Thesystem includes a long, flexible, thin and preferably disposablecatheter 220, a balloon/Stent 222. an endoscope imaging head 224, anX-ray tube 226, X-ray imaging system 228, a video display system 230 andan injection unit 232.

[0225] Intra Vascular procedures are widely used in the medical field.Among various intra-vascular procedures, cardiac catheterization is avery common diagnostic test performed thousands of times a day. Duringthe procedure, catheter 220 is inserted into an artery at the groin orarm. The catheter is directed retrogradely to the heart and to theorigin of the coronary arteries, which supply blood to the heart muscle.A contrast substance (“dye”) is injected through the catheter. The useof an x-ray tube, and an endoscope in conjunction with the dye enables aview of the heart chambers and coronary arteries to be obtained. Theresulting images may be recorded using an x-ray camera and/or theendoscope systems as described above. If an obstruction is detected inone or more of the coronary arteries, the obstruction may be removed andthe artery reopened using techniques such as inserting the balloon andinflating it (PTCA) or inserting a stent, as known to the person skilledin the art.

[0226] In intra-vascular operation generally, a few methods may be usedto acquire intra-vascular images in the presence of blood. One method isbased on the fact that certain near IR wavelengths allow viewing throughblood. The method thus involves the use of an IR illumination source anda sensor with IR filters as described above. Another method usescontrolled injection of a transparent physiological liquid into theblood vessel in order to dilute the blood prior to the imaging. Yetanother method uses a conical dome, a balloon or any other rigid orflexible and inflatable transparent structure in order to improvevisibility by “pushing” the blood to the walls of the vessels, thusenlarging the part of the optical path that does not include blood.Another way of improving visibility is by using a post-processingalgorithm after the acquiring of the image has been done. Thepost-processing algorithm is based on the extraction of parameters fromthe received image and the use of those parameters in an inverseoperation to improve the image.

[0227] There is thus provided an endoscope of reduced dimensions whichis able to provide 2D and 3D images, and which is usable in a range ofminimally invasive surgical procedures.

[0228] It is appreciated that certain features of the invention, whichare, for clarity, described in the context of separate embodiments, mayalso be provided in combination in a single embodiment. Conversely,various features of the invention which are, for brevity, described inthe context of a single embodiment, may also be provided separately orin any suitable subcombination.

[0229] It will be appreciated by persons skilled in the art that thepresent invention is not limited to what has been particularly shown anddescribed hereinabove. Rather the scope of the present invention isdefined by the appended claims and includes both combinations andsubcombinations of the various features described hereinabove as well asvariations and modifications thereof which would occur to personsskilled in the art upon reading the foregoing description.

In the claims:
 1. (Original) A pixilated image sensor for insertionwithin a restricted space, the sensor comprising a plurality of pixelsarranged in a selected image distortion pattern, said image distortionpattern being selected to project an image larger than said restrictedspace to within said restricted space substantially with retention of animage resolution level.
 2. (Original) A pixilated image sensor accordingto claim 1 wherein said image distortion pattern is a splitting of saidimage into two parts and wherein said pixilated image sensor comprisessaid pixels arranged in two discontinuous parts.
 3. (Original) Apixilated image sensor according to claim 2, wherein said discontinuousparts are arranged in successive lengths.
 4. (Original) A pixilatedimage sensor according to claim 2, wherein said restricted space is aninterior longitudinal wall of an endoscope and wherein saiddiscontinuous parts are arranged on successive lengths of said interiorlongitudinal wall.
 5. (Original) A pixilated image sensor according toclaim 3, wherein said restricted space is an interior longitudinal wallof an endoscope and wherein said discontinuous parts are arranged onsuccessive lengths of said interior longitudinal wall.
 6. (Original) Apixilated image sensor according to claim 1, wherein said distortionpattern is an astigmatic image distortion.
 7. (Original) A pixilatedimage sensor according to claim 6, wherein said distortion pattern is aprojection of an image into a rectangular shape having dimensionspredetermined to fit within said restricted space.
 8. (Original) Apixilated image sensor according to claim 1, including one of a groupcomprising CMOS-based pixel sensors and CCD based pixel sensors. 9.(Original) A pixilated image sensor according to claim 1 controllable toco-operate with alternating image illumination sources to producecorresponding illuminated images for each illumination source. 10.(Original) An endoscope having restricted dimensions and comprising atleast one image gatherer, at least one image distorter and at least oneimage sensor shaped to fit within said restricted dimensions, andwherein said image distorter is operable to distort an image receivedfrom said image gatherer so that the image is sensible at said shapedimage sensor substantially with an original image resolution level. 11.(Original) An endoscope according to claim 10, wherein said imagedistorter comprises an image splitter operable to split said image intotwo part images.
 12. (Original) An endoscope according to claim 11wherein said image sensor comprises two sensor parts, each separatelyarranged along longitudinal walls of said endoscope.
 13. (Original) Anendoscope according to claim 12, wherein said two parts are arranged insuccessive lengths along opposite longitudinal walls of said endoscope.14. (Original) An endoscope according to claim 10, wherein saiddistorter is an astigmatic image distorter.
 15. (Original) An endoscopeaccording to claim 14, wherein said astigmatic image distorter is animage rectangulator and said image sensor comprises sensing pixelsrearranged to complement rectangulation of said image by said imagerectangulator.
 16. (Original) An endoscope according to claim 10,wherein said image distorter comprises at least one lens.
 17. (Original)An endoscope according to claim 16, wherein said image distortercomprises at least one image-distorting mirror.
 18. (Original) Anendoscope according to claim 16, wherein said image distorter comprisesoptical fibers to guide image light substantially from said lens to saidimage sensor.
 19. (Original) An endoscope according to claim 16, whereinsaid image distorter comprises a second lens.
 20. (Original) Anendoscope according to claim 17, wherein said image distorter comprisesat least a second image-distorting mirror.
 21. (Original) An endoscopeaccording to claim 16, wherein said image distorter comprises at leastone flat optical plate.
 22. (Original) An endoscope according to claim10, further comprising at least one light source for illuminating anobject, said light source being controllable to flash at predeterminedtimes.
 23. (Original) An endoscope according to claim 22 furthercomprising a second light source, said first and said second lightsources each separately controllable to flash.
 24. (Original) Anendoscope according to claim 23, wherein said first light source is awhite light source and said second light source is an a source ofinvisible light radiation.
 25. (Original) An endoscope according toclaim 24, wherein said second light source is an IR source. 26.(Original) An endoscope according to claim 24, wherein said second lightsource is a UV light source.
 27. (Original) An endoscope according toclaim 23, one light source being a right side light source forilluminating an object from a first side and the other light sourcebeing a left side light source for illuminating said object from asecond side.
 28. (Original) An endoscope according to claim 25, onelight source comprising light having a first spectral response and theother light source comprising light having a second spectral response.29. (Original) An endoscope according to claim 27 further comprisingcolor filters associated with said light gatherer to separate light fromsaid image into right and left images to be fed to respective right andleft distance measurers to obtain right and left distance measurementsfor construction of a three-dimensional image.
 30. (Original) Anendoscope according to claim 27, said light sources being configured toflash alternately.
 31. (Original) An endoscope according to claim 27,further comprising a relative brightness measurer for obtaining relativebrightnesses of points of said object using respective right and leftillumination sources, thereby to deduce 3 dimensional distanceinformation of said object for use in construction of a 3 dimensionalimage thereof.
 32. (Original) An endoscope according to claim 22,further comprising a second image gatherer and a second image sensor.33. (Original) An endoscope according to claim 32, wherein one of saidimage sensors is a color image sensor and a second of said image sensorsis a monochrome image sensor.
 34. (Original) An endoscope according toclaim 32, wherein said first and said second image sensors are arrangedback to back longitudinally within said endoscope.
 35. (Original) Anendoscope according to claim 32, wherein said first and said secondimage sensors are arranged successively longitudinally along saidendoscope.
 36. (Original) An endoscope according to claim 35, whereinsaid first and said second image sensors are arranged along alongitudinal wall of said endoscope.
 37. (Original) An endoscopeaccording to claim 10, comprising a brightness averager operable toidentify brightness differentials due to variations in distances fromsaid endoscope of objects being illuminated, and substantially to cancelsaid brightness differentials.
 38. (Original) An endoscope according toclaim 37, further comprising at least one illumination source forilluminating an object with controllable width light pulses and whereinsaid brightness averager is operable to cancel said brightnessdifferentials by controlling said widths.
 39. (Original) An endoscopeaccording to claim 10, having at least two controllable illuminationsources, one illumination source for emitting visible light to produce avisible spectrum image and one illumination source for emittinginvisible light to produce a corresponding spectral image, saidendoscope being controllable to produce desired ratios of visible andinvisible corresponding spectral images.
 40. (Original) An endoscopesystem comprising an endoscope and a controller, said endoscopecomprising: at least one image gatherer, at least one image distorterand at least one image sensor shaped to fit within restricted dimensionsof said endoscope, said image distorter being operable to distort animage received from said image gatherer so that the image is sensible atsaid shaped image sensor with retention of image resolution, saidcontroller comprising a dedicated image processor for processing imageoutput of said endoscope.
 41. (Original) An endoscope system accordingto claim 40, wherein said dedicated image processor is a motion videoprocessor operable to produce motion video from said image output. 42.(Original) An endoscope system according to claim 40, wherein saiddedicated image processor comprises a 3D modeler for generating a 3Dmodel from said image output.
 43. (Original) An endoscope systemaccording to claim 42, wherein said dedicated image processor furthercomprises a 3D imager operable to generate a stereoscopic display fromsaid 3D model.
 44. (Original) An endoscope system according to claim 40,comprising an image recorder for recording imaging.
 45. (Original) Anendoscope system according to claim 40, comprising a control and displaycommunication link for remote control and remote viewing of said system.46. (Original) An endoscope system according to claim 40, wherein saidimage distorter comprises an image splitter operable to split said imageinto two part images.
 47. (Original) An endoscope system according toclaim 40, wherein said image sensor comprises two sensor parts, eachseparately arranged along longitudinal walls of said endoscope. 48.(Original) An endoscope system according to claim 47, wherein said twoparts are arranged in successive lengths along opposite longitudinalwalls of said endoscope.
 49. (Original) An endoscope system according toclaim 40, wherein said distorter is an astigmatic image distorter. 50.(Original) An endoscope system according to claim 49, wherein saidastigmatic image distorter is an image rectangulator and said imagesensor comprises sensing pixels rearranged to complement rectangulationof said image by said image rectangulator.
 51. (Original) An endoscopesystem according to claim 40, wherein said image distorter comprises atleast one lens.
 52. (Original) An endoscope system according to claim51, wherein said image distorter comprises at least one image-distortingmirror.
 53. (Original) An endoscope according to claim 51, wherein saidimage distorter comprises optical fibers to guide image lightsubstantially from said lens to said image sensor.
 54. (Original) Anendoscope system according to claim 51, wherein said image distortercomprises a second lens.
 55. (Original) An endoscope system according toclaim 51, wherein said image distorter comprises at least a secondimage-distorting mirror.
 56. (Original) An endoscope system according toclaim 50, wherein said image distorter comprises at least one flatoptical plate.
 57. (Original) An endoscope system according to claim 40,further comprising at least one light source for illuminating an object.58. (Original) An endoscope system according to claim 56, furthercomprising a second light source, said first and said second lightsources each separately controllable to flash.
 59. (Original) Anendoscope system according to claim 57, wherein said first light sourceis a white light source and said second light source is an invisiblelight source.
 60. (Original) An endoscope system according to claim 58,one light source being a right side light source for illuminating anobject from a first side and the other light source being a left sidelight source for illuminating said object from a second side. 61.(Original) An endoscope system according to claim 60, one light sourcecomprising light of a first spectral response and the other light sourcecomprising light of a second spectral response.
 62. (Original) Anendoscope system according to claim 61, further comprising color filtersassociated with said light gatherer to separate light from said imageinto right and left images to be fed to respective right and leftdistance measurers to obtain right and left distance measurements forconstruction of a three-dimensional image.
 63. (Original) An endoscopesystem according to claim 61, said light sources being configured toflash alternately.
 64. (Original) An endoscope system according to claim61, said light sources being configured to flash simultaneously. 65.(Original) An endoscope system according to claim 61, further comprisinga relative brightness measurer for obtaining relative brightnesses ofpoints of said object using respective right and left illuminationsources, thereby to deduce 3 dimensional distance information of saidobject for use in construction of a 3 dimensional image thereof. 66.(Original) An endoscope system according to claim 57, further comprisinga second image gatherer and a second image sensor.
 67. (Original) Anendoscope system according to claim 65, wherein said first and saidsecond image sensors are arranged back to back longitudinally withinsaid endoscope.
 68. (Original) An endoscope system according to claim65, wherein said first and said second image sensors are arrangedsuccessively longitudinally along said endoscope.
 69. (Original) Anendoscope system according to claim 67, wherein said first and saidsecond image sensors are arranged along a longitudinal wall of saidendoscope.
 70. (Original) An endoscope system according to claim 40,comprising a brightness averager operable to identify brightnessdifferentials due to variations in distances from said endoscope ofobjects being illuminated, and substantially to reduce said brightnessdifferentials.
 71. (Original) An endoscope for internally producing animage of a field of view, said image occupying an area larger than across-sectional area of said endoscope, the endoscope comprising: animage distorter for distorting light received from said field of viewinto a compact shape, and an image sensor arranged in said compact shapeto receive said distorted light to form an image thereon. 72.-75.(Cancelled)
 76. (Original) An endoscope according to claim 71, saidimage distorter comprising an astigmatic lens shaped to distort a squareimage into a rectangular shape of substantially equivalent area. 77.(Original) An endoscope according to claim 71, further comprising acontrast equalizer for compensating for high contrasts differences dueto differential distances of objects in said field of view. 78.(Original) An endoscope according to claim 71, comprising twoillumination sources for illuminating said field of view.
 79. (Original)An endoscope according to claim 78, said illumination sources beingcontrollable to illuminate alternately, and said image sensor beingcontrollable to gather images in synchronization with said illuminationsources thereby to obtain independently illuminated images. 80.(Original) An endoscope according to claim 78, each illumination sourcehaving a different predetermined spectral response.
 81. (Original) Anendoscope according to claim 80, said image sensor comprising pixels,each pixel being responsive to one of said predetermined spectralresponses.
 82. (Original) An endoscope according to claim 71, said imagesensor comprising a plurality of pixels responsive to white light. 83.(Original) An endoscope according to claim 71, said image sensorcomprising a plurality of pixels responsive to different wavelengths oflight.
 84. (Original) An endoscope according to claim 83, saidwavelengths comprising at least three of red light, green light, bluelight and infra-red light.
 85. (Original) An endoscope according toclaim 71, further comprising a second image sensor for forming a secondimage from light obtained from said field of view.
 86. (Original) Anendoscope according to claim 85, wherein one of said image sensors is acolor sensor and a second of said image sensors is a monochrome sensor.87. (Original) An endoscope according to claim 85, said second imagesensor being placed in back to back relationship with said first imagesensor over a longitudinal axis of said endoscope.
 88. (Original) Anendoscope according to claim 85, said second image sensor being placedin end to end relationship with said first image sensor along alongitudinal wall of said endoscope.
 89. (Original) An endoscopeaccording to claim 85, said second image sensor being placed across fromsaid first image sensor on facing internal longitudinal walls of saidendoscope.
 90. (Original) A compact endoscope for producing 3D images ofa field of view, comprising a first image sensor for receiving a view ofsaid field through a first optical path and a second image sensor forreceiving a view of said field through a second optical path, andwherein said first and said second image sensors are placed back to backalong a longitudinal axis of said endoscope.
 91. (Original) A compactendoscope for producing 3D images of a field of view, comprising a firstimage sensor for receiving a view of said field through a first opticalpath and a second image sensor for receiving a view of said fieldthrough a second optical path, and wherein said first and said secondimage sensors are placed end to end along a longitudinal wall of saidendoscope. 92 (Original) A compact endoscope for producing 3D images ofa field of view, comprising two illumination sources for illuminatingsaid field of view, an image sensor for receiving a view of said fieldilluminated via each of said illumination sources, and a viewdifferentiator for differentiating between each view.
 93. (Original) Acompact endoscope according to claim 92, wherein said differentiator isa sequential control for providing sequential operation of saidillumination sources.
 94. (Original) A compact endoscope according toclaim 87, wherein said illumination sources are each operable to produceillumination using respectively different spectral responses and saiddifferentiator comprises a series of filters at said image sensor fordifferentially sensing light having said respectively different spectralresponses.
 95. (Original) A compact endoscope according to claim 71,wherein said image distorter comprises a plurality of optical fibers forguiding parts of a received image to said image sensor according to saiddistortion pattern.
 96. (Original) A method of manufacturing a compactendoscope, comprising: providing an illumination source, providing animage distorter, providing an image ray diverter, providing an imagesensor whose shape has been altered to correspond to a distortion builtinto said image distorter, said distortion being selected to reduce atleast one dimension of said image sensor to less than that of anundistorted version being sensed, assembling said image distorter, saidimage ray diverter and said image sensor to form an optical path withinan endoscope
 97. (Original) A method of obtaining an endoscopic imagecomprising: illuminating a field of view, distorting light reflectedfrom said field of view such as to form a distorted image of said fieldof view having at least one dimension reduced in comparison to anequivalent dimension of said undistorted image, and sensing said lightwithin said endoscope using at least one image sensor correspondinglydistorted.